“By having firearms officers on board trains we’re ensuring that trains remain as safe as possible for passengers.

“Our patrols will be highly visible and passengers should feel comforted by their presence. Please do speak to them if you have any concerns at all.

“This is part of our national mobilisation plan to deal with the current and ongoing threat.

“It is important to note that we do not have any specific intelligence in relation to train services but are taking this action to ensure we can protect and reassure the public.”

He said since the Government enacted Operation Temperer, BTP has been reinforced by additional firearms officers from the Ministry of Defence Police, who will remain at stations in London.

Chief Constable Crowther added: “I want to take this opportunity to remind everyone to stay calm, be vigilant, and if you spot anything at all which gives you cause for concern, let us know.

“In light of the dreadful events over these last few days, and the increase to the national threat level, nothing should be considered too trivial to report and any information – regardless of whether you feel it is significant or not – may be important to all of us.

“The cowardly acts of terrorists will never weaken our resolve. We will continue to work with police forces nationally to ensure that the travelling public remain safe and reassured.”

Jack is a business and economics journalist and the founder of The London Economic (TLE).
He has contributed articles to The Sunday Telegraph, BBC News and writes for The Big Issue on a weekly basis.
Jack read History at the University of Wales, Bangor and has a Masters in Journalism from the University of Newcastle-upon-Tyne.